BTRFS_INODE_COW_WRITE_ERROR
clear_bit(BTRFS_INODE_COW_WRITE_ERROR, &inode->runtime_flags);
if (test_and_clear_bit(BTRFS_INODE_COW_WRITE_ERROR, &inode->runtime_flags))
set_bit(BTRFS_INODE_COW_WRITE_ERROR, &inode->runtime_flags);